1. Field of the Invention
This invention relates in general to vehicle dispatch systems, and in particular to the communication of assignment messages within vehicle dispatch systems.
2. Description of the Related Art
A number of vehicle dispatch systems exist for the tracking and controlling of fleets such as taxicabs, delivery trucks, and the like. These systems typically communicate requests for dispatch to the vehicles in the fleet and then match acceptance of the request to the particular request. Key criteria of vehicle dispatch systems, whether manual or automatic, simple or complex, include the system cost, the system performance, and the fairness and timeliness of the selection process.
Historically, two-way radio networks have been utilized for vehicle dispatch. Voice communication is the primary communication tool for information gathering and decision making relating to the distribution of assignments in these systems. A dispatch center broadcasts a message of a new assignment location either via a data network or a voice network to the drivers of the various vehicles in the fleet; and each individual driver replies with his/her acceptance or rejection of the assignment to the dispatch center. Typically, the driver's reply is accomplished via a voice network such as a cellular phone or two-way radio.
There are several drawbacks to these vehicle dispatch systems. First, the driver must be alert at all times to listen to the assignment messages from the dispatch center and rapidly determine if the assignment location is within his/her range. The driver must make a quick decision for each message of whether to accept the job or not. In some fleets, if the driver affirmatively replies to the dispatch center and then does not get to the assignment location within a predetermined amount of time he can be fined. The combination of the rapid assignment messaging and decision-making and the potential for fines creates high stress levels in the drivers of the vehicles.
A second drawback of the traditional vehicle dispatch systems is that some of the drivers will answer any call, even if not close to the assignment location, motivated by a desire to maximize income or challenge the system. This creates an environment wherein the customer suffers from not receiving the most rapid service. Further, drivers from competing fleets can monitor the frequency of message transmission with a scanner and "steal" the assignments from the drivers who the message was targeted to reach.
Further, the broadcast of the assignment message in traditional vehicle dispatch systems is made throughout the entire territory covered by the fleet. In areas where there is a shortage of radio frequency channels, the available channels are rapidly filled to capacity. The expense of maintaining existing channels and/or petitioning the local government for new channels can be out of reach for many dispatch businesses.
Today, vehicle dispatch systems designed to alleviate some of the previously described drawbacks typically focus communications and decision-making at the dispatch center. Information such as geographical location and current job status of a selected vehicle is established; and then decisions regarding sending the current dispatch message to that selected vehicle are made by comparing that information either manually or automatically to some predefined criteria in the dispatch center. Automatic vehicle locator systems that automatically track the location of managed vehicles and then report this information to a dispatcher are frequently utilized. Advanced automatic vehicle locator systems further automatically identify the nearest vehicle to a location to further facilitate the dispatcher's accuracy. In some systems, the geographical location is compared to known locations of authorized vehicles and dispatch of the message is denied to the selected vehicle if the selected vehicle's location does not correspond to one of the known locations.
Other vehicle dispatch systems automatically assign jobs to the closest available vehicle and then inform the driver of the assignment via some other channel, such as the driver's mobile pager. In this method, no assurance is given that the driver receives the notification or is actually available to take the assignment. The driver actually has no method to decline the assignment in this type of system.
The drawback of all of these systems is that the control rests within the dispatch center completely and the complexity of the system communications is increased greatly. Further the channel utilization increases since each call must be sent individually to each selected driver. Lastly, the systems still rely heavily on the dispatcher to make decisions and perform monitoring of the vehicles. This leads to a high degree of errors and confusion.
What is needed is a method to reduce the loading of the channels used for vehicle dispatch, reduce the decision-making stress on the vehicle drivers, and at the same time retain the automatic sorting mechanisms of the dispatch center-based systems.